The name says it all: Free money is simply money that is credited to your account at no extra charge.
You can do whatever you want with this money. You can spend it on the casino games, or withdraw it whenever you like.
Since it’s real money and not bonus money, there are no wagering requirements that you have to meet and once you have free money in your account you can withdraw it.
You won’t find many promotions from a casino that reward you with free money. There are, however, some very good free money offers, although you may have to search persistently to find them.
Other more common types of bonuses, such as free spins and bonus money, tend to be favored by online casino operators.
To recap, the bonus money usually has to be wagered before you can make withdrawals but with free money offers, you can withdraw it immediately.